Wiring Methods — General Requirements

Article 300 is the foundation that the rest of Chapter 3 builds on. Rather than restating the same protections inside every cable and conduit article, the Code collects them here: minimum burial depths, protection from physical damage where conductors pass through framing, sealing against moisture, keeping conductors of the same circuit grouped so their magnetic fields cancel, and firestopping penetrations.

These general rules grew out of decades of field failures — conductors chewed by nails, water wicking into fittings, induced heating from splitting a circuit across separate metal raceways. Reading Article 300 first makes every later article shorter and clearer.

When it applies

Article 300 is the umbrella over nearly every wiring method, so its rules follow you across the whole job. It covers burial depths, protection where cables pass through framing, securing and supporting, and keeping moisture out of raceways. If a more specific article is silent, these general rules still govern.

Common mistakes

• Burying conductors shallower than the required depth for the method and voltage.
• Skipping nail plates where cable runs close to the face of a stud.
• Ignoring the drain and moisture provisions so raceways collect condensation.

In the field

On an industrial run I treat these general rules as the baseline before I open the specific conduit article. Get the burial depth, support spacing, and physical protection right and the rest of the install follows cleanly.